DTS-HD Master Audio
DTS-HD Master Audio is an extension of DTS' previous DTS Coherent Acoustics codec. Prior to 2004, it had been known as DTS++. Though it is an optional audio format for Blu-ray Disc format, by 2010, it had become the dominant Blu-ray lossless audio format over its competitor Dolby TrueHD. DTS-HD Master Audio is also the carrier for home delivery of DTS:X.
DTS-HD Master Audio is a lossless compression codec containing a lossy DTS Digital core, thus allowing for bit-to-bit representation of the original movie's master soundtrack. DTS-HD Master Audio supports variable bit rates up to 24.5 Mbit/s on a Blu-ray Disc and up to 18.0 Mbit/s for HD DVD. The format supports a maximum of 192 kHz sampling frequency and 24-bit depth samples from 2 to 5.1 channels, and 96 kHz/24bit resolution up to 7.1 channels. DTS-HD is capable of virtually any number of discrete channels but is limited by storage media.
As a 3D audio delivery format, a DTS:X encoded DTS-HD Master Audio stream is able to contain up to 7.1 channels as well as nine objects and its associated metadata at 96 kHz/24 bit.
Combined lossless/lossy compression
According to the DTS-HD White Paper, DTS-HD Master Audio contains 2 data streams: the original DTS core stream and the additional "residual" stream which contains the "difference" between the original signal and the lossy compression DTS core stream. The audio signal is split into two paths at the input to the encoder. One path goes to the core encoder for backwards compatibility and is then decoded. The other path compares the original audio to the decoded core signal and generates residuals, which are data over and above what the core contains that is needed to restore the original audio as bit-for-bit identical to the original. The residual data is then encoded by a lossless encoder and packed together with the core. The decoding process is simply the reverse.
- Over 6, 7 or 8 RCA connectors as analog audio (not lossless), using the player's internal decoder and digital-to-analog converter (DAC).
- Over HDMI 1.1 (or higher) connections as 6-, 7- or 8-channel linear PCM, using the player's decoder and the AV receiver's DAC.
- Over HDMI 1.3 (or higher) connections as the original DTS-HD Master Audio bitstream, with decoding and DAC both done by the AV receiver.
- Dolby TrueHD, a competing audio codec
- Thomson, Kristin (2004-11-01). "DTD Unveils DTS-HD Brand For High Definition Media Formats". Retrieved 2009-05-06.
- "DTS-HD Master Audio Becoming the Blu-ray Standard". Blu-raystats.com. January 15, 2010. Retrieved November 15, 2010.
- "DTS-HD Master Audio Specifications (DTS-HD Master Audio™ - DTS)". January 10, 2012.
- Morrison, Geoffrey (September 23, 2009). "Dolby Pro Logic IIz vs. Audyssey DSX vs. DTS". Home Entertainment. Retrieved November 15, 2010.
- "Lookout Dolby Atmos, DTS just entered the next era of surround sound with DTS:X". Digital Trends. 2015-04-13. Retrieved 2016-06-09.
- This feature is also offered by unrelated codecs OptimFROG DualStream, WavPack Hybrid and MPEG-4 SLS.
- "DTS-HD Audio: Consumer White Paper for Blu-ray Disc and HD DVD Applications". November 2006. Retrieved 2009-05-06.